The present invention relates to a cassette loading apparatus for digital audio tape recorder (DAT) and more specifically relates to a cassette front loading apparatus for a DAT having tray type loading effected by moving a cassette horizontally and vertically.
A conventional DAT is formed such that a tape cassette containing an audio tape is positioned on reel tables within an interior of the apparatus, the tape is drawn out of the cassette and connected to a rotary head drum, thereafter the tape is driven by the driving force of a capstan motor, whereby recording and reproduction of the tape can be executed. In such a DAT, a practical form of the conventional cassette front loading apparatus for moving a tape cassette from the exterior to the interior of an apparatus will be explained in detail with reference to FIGS. 1 to 3 as follows.
In FIGS. 1, 2 and 3 of the drawings, the reference numeral 1 is a base plate, 2 is a cassette tray reciprocally and linearly movable against the base plate 1, 3 is a cassette holder which carries a DAT cassette 70 (refer to FIGS. 4 and 5) by moving with the tray 2, 4 is a loading motor for loading the cassette tray 2 and the cassette holder 3, 5 is a cassette lift and drop motor which moves downwardly a predetermined length successively from the state when the cassette holder 3 finished the horizontal movement, 6 is a slider opening plate which opens a slider 74 of a cassette 70, 7 is a push lever which properly and safely sets the cassette 70 into the cassette holder 3 when loading a cassette 70, 8 is a take out lever which takes out said cassette 70 from the cassette holder 3 when loading another cassette 70, 9 is a driving gear which transfers the driving force of the cassette lift and drop motor 5, 10 is an opening operation plate which actuates the slider opening plate 6 by being coupled with the driving gear 9, and 11 represents a lift and drop operation plate which drops the cassette holder and the cassette 70 by being coupled with the driving gear 9, respectively.
Guide bars 12 are affixed tightly to the sides of the base plate 1 and linear bearings 14 are arranged on both side plates 13 of said cassette tray 2 into which the guide bars 12 are inserted so that the cassette tray 2 linearly, rides along the guide bars 12.
The side plates 15 of the cassette holder 3 are movably connected to the respective rotation lever 16 by connecting pieces 17 and each rotation lever is rotatably fixed at the respective side plate 13 of the cassette tray 2 by axial pins 18, the axial pins 18 holding torsion springs 19 that resiliently supports the rotation levers 16 in a clockwise direction.
The loading motor 4 is fixed to the base plate 1. A pulley 22 is mounted on the bottom of the base plate 1, the pulley 22 being connected via a belt 21 to a pulley 20 fixed to a shaft of the loading motor 4. A gear 24 is connected to a gear 23 formed integrally therewith, a pulley 25' connected by a belt 26 to a pulley 25 formed integrally therewith, and the belt 26 is connected to connecting pieces 27 affixed to the cassette tray 2. Therefore, the cassette tray 2, cassette holder 3, rotation lever 16 and take out lever 8 can be moved together linearly.
The lift and drop motor 5, to which shaft a pulley 28 is fixed, is connected to a pulley 30 formed integrally with a worm 29 by a belt 31, and the worm 29 is meshed with the driving gear 9. At the lower surface of the driving gear 9, a small gear having a cam groove 33 at the peripheral surface thereof is integrally formed and is meshed with a rack 34 formed at a side edge portion of said lift and drop operation plate 11. At the lower portion of the driving gear 9, a cam lever 36 is rotatably mounted with a shaft pin 35 and a cam pin 37 provided on the upper surface of the cam lever 36 is inserted into the cam groove 33 of the driving gear 9 and, at the same time, another cam pin 37' is inserted into a rectangular guide hole 39 of the opening operation plate 10 through a pierced hole 38 formed at the based plate 1, and the cam lever 36 and the opening operation plate 10 are connected by a tension spring 40.
The opening operation plate 10 is connected to the slider opening plate 6 by a shaft 41, the slider opening plate 6 and the opening operation plate 10 being connected to one and other by a tension spring 42. The slider opening plate 6 is formed with a cassette hooking piece 43 at a front end portion and a contacting piece 44 is formed at a rear portion, whereby the contacting piece 44 is allowed to contact a 2-stage cam step portion 45 mounted on the lift and drop operation plate 11.
At a side of the lift and drop operation plate 11 of the base plate 1 there is affixed a rotation relay lever 46 by a shaft 48 on a supporting piece 47 protruding from the base plate 1. The lever is urged by a tension spring 49. When the lift and drop operation plate 11, moves forward the lever 46 it is pushed by its protrusion 50 and the lever 46 accordingly rotates the rotation lever 16.
The push lever 7 is formed such that when the cassette tray 2 is loaded, it rotates, contacting a contact plate 51 which is formed by being bent downwardly at a frontward portion of the base plate 1, and it is allowed to rotate a push bar 52 through the gear and the coupling movement mechanism of the cam.
The cassette take out lever 8 is fixed by a shaft pin 54 at a supporting plate 53 fixed between both side plates 13, 13 of the cassette tray 2. The take out lever 8 and the supporting plate 53 are connected by a tension spring 55 which resiliently urges the take out lever 8 counter clockwise, and it is formed such that an inclined cam 56 is fixed to a predetermined portion of the base plate 1 so that the take out plate 8 is slides.
The rotating direction, starting, stopping, etc. of the loading motor 4 and cassette lift and drop motor 5, are determined in accordance with the combination of ON/OFF signals of the first, second, third and fourth location detecting switches 61, 62, 63, 64 fixed respectively at a predetermined location on the base plate 1.
FIGS. 4 and 5 show a DAT cassette. As shown in the drawings, a tape cassette 70 is provided such that a slider 74 can be opened and closed in a sliding manner with respect to a main body 73 in which a magnetic tape 71 is wound on reels 72. The reel hub exposing holes 75 are formed on both sides of the main body 73. The slider 74 is formed with pierced holes 76 which are aligned with the reel hub exposing hole 75 of the main body 73 when it is open. A guide hole 77 is provided adjacent both sides of the pierced hole 76 for receiving the release protrusion 57 of the cassette holder 3. At the same time the front portion of each of the guide holes 77 are formed to have a lock hole 79 for receiving, a lock 78 protruding from the interior of the main body 73, and a protect cover 80 is coupled by a hinge to the main body 73. A groove 81 into which the hooking piece 58 of the cassette holder 3 is inserted is formed in the cover 80.
A DAT cassette of this type is loaded and unloaded into the interior of DAT by the front loading apparatus, the loading operation being executed by a step in which it is carried on the cassette holder 3 and moved a predetermined distance into the interior of the apparatus and by a step by which the cassette is moved vertically and set safely and properly on the reel table mounted at the base plate 1, the slider 74 being opened at the time of horizontal movement and the protecting cover 80 being opened at the time of vertical movement.
The loading and unloading operation of a cassette in accordance with the conventional cassette front loading apparatus as described hereinbefore is as follows.
FIGS. 1, 2 and 3A show the state when a cassette tray is ejected. At this moment a protrusion 59 of the connecting piece 27 fixed at a cassette tray 2 contacts a first location detecting switch 61 which turns on and the loading motor 4 is stopped.
In this condition, a cassette 70 is put in a cassette tray 2 and when the cassette tray 2 is pushed slightly inwardly (rearwardly), the first location detecting switch 61 turns off and the loading motor 4 rotates positively, the cassette tray 2 together with the cassette holder 3 and the cassette 70 are pushed inwardly, the push bar 52 moves from the guide hole 60 of the cassette tray 2 through the gear and the coupling movement mechanism of the lever when the push lever 7 being contacted by the contact plate 51 and then rotated, the cassette 70 is pushed by push bar 52 and is slightly moved inwardly and the release protrusion 57 of the cassette holder 3 is inserted into its guide groove 77 and the lock of slider 74 is released at the same time the hooking piece 58 is inserted into the inserting hole 81 to which hooking piece 58 of the front edge portion of slider 81 is hooked up, and it is supported stably by which the top surface is pressed into the rubber pressing roller 65 fixed adjacent to the connecting piece 15 of cassette holder 3. After the cassette 70 is set stably in the cassette holder 3 in this condition the cassette tray 2, cassette holder 3 and cassette 70 are moved continuously to inwardly by the driving power of the loading motor 4. Then the protrusion 66' formed at a side plate 13 of cassette tray 2 actuates the second location detecting switch 62 which is thereby turned on, and then the loading motor 4 is stopped and the horizontal movement of the cassette tray 2 is completed. Subsequently the cassette lift and drop motor 5 is rotated and the worm 29 and driving gear 9 are rotated and then the lift and drop driving plate 11 meshed with the small gear 32 of the driving gear 9 are moved frontwardly and then the protruded piece 66 moves away from the third location detecting switch 63 and the third location switch 63 turns. When the lift and drop operation plate 11 is moved, the contact piece 44 of the slider opening plate 6 contacting the cam step portion 45 is lifted up, and the slider opening plate 6 is rotated counterclockwise (based on FIG. 1) around the shaft 41 and contacts the top surface of the cassette 70. The driving gear 9 is rotated continuously by the driving power of driving motor 5, the lift and drop plate 11 is kept moving frontwardly at the same time the opening operation plate 10 is moved rearwardly by the operation of the cam lever 36 and the cam groove 33 of the bottom surface of driving gear 9 and the slider opening plate 6 are moved together rearwardly. Thus the slider opening plate is moved, and the hooking piece 43 hooks the cassette main body 73 and moves, whereby the cassette main body 73 is moved together. At this moment the slider 74 is hooked to the cassette holder 3 and the movement is stopped, whereby the slider 74 is opened and its pierced hole 76 and the reel hub exposing hole 57 of main body 73 are aligned with one another.
Thereafter, since the driving gear continues rotating, the cam lever 36 cooperatively moves along with the cam groove 33, whose pin 37 contacts the concentric circle portion of the cam groove 33. The rotation is stopped at the same time, and accordingly the opening operation plate 10 and the slider opening plate 6 also are stopped, but the lift and drop plate 11 are allowed to keep moving frontwardly as in FIG. 3B, the protrusion 50 on which lift and drop plate 11 rotates the rotation relay lever 46. Upon rotating relay lever 16, the cassette holder 3 connected thereto is moved downwardly and vertically and is set stably on the reel table coupled to the predetermined portion of the base plate 1. At this moment the protrusion 67 protruding from the lift and drop plate 11 actuates the fourth location detecting switch 64. Then the cassette lift and drop motor 5 is made to stop.
In the above described process, summarizing the operation of the location detecting switches, if the state when the first to fourth location detecting switches 61-64 are depressed is supposed to be ON, in case of ejecting when the first location detecting switch 61 is ON then the loading motor 4 and the lift and drop motor 5 must stop; when the first location detecting switch 61 is OFF and the third location detecting switch 63 is ON then the loading motor 4 must positively rotate and continue to rotate until the second location detecting switch 62 is ON; when the second location detecting switch 62 is ON when the third location detecting switch 63 is ON then the loading motor 4 must stop and the lift and drop motor 5 is rotated positively and the cassette 70 must seat on the reel tables. When the cassette is set then the fourth location detecting switch 64 turns ON by contact with the protrusion 67 of the lift and drop operation plate 11 and the lift and drop motor 5 must stop and to recognize the state of the cassette 70 being set.
When the cassette 70 is set on the reel tables, the tape 71 contained in the cassette 70 is drawn by the tape running mechanism and is applied to a rotary head drum and caused to run by the driving power of the capstan motor, the recording or reproducing then being executed (the rotary head drum, capstan motor and tape running mechanism are not shown in drawings).
After the playing and recording are executed as described above, when it is intended to eject the cassette, the ejection is effected by the reverse of the above procedure, such that when the cassette tray 2 is moved frontwardly and horizontally, the contact piece 68 of the take out lever 8 connected thereof contacts the inclined cam 56 fixed to the base plate 1 and is rotated in clockwise around the shaft pin 54, and the cassette 70 by which the take out piece 69 is adhered with pressure to the cassette holder 3 by the rubber pressure roller 65 is pushed out slightly forward so that a user can easily take out the cassette 70.
Since a conventional DAT front loading apparatus as described above uses the loading motor in order to move the cassette holder and cassette horizontally, and it uses the lift and drop motor in order to move the cassette holder and cassette vertically, both loading and unloading motors are required for loading and unloading of the cassette. Also, since it is formed with very complicated structure in requiring a device for setting the cassette at the cassette holder stably, a device for moving the cassette horizontally, a device for opening the slider, a device for lifting and dropping the cassette, a take out device to take out the cassette easily from the cassette holder, and the location detecting switch device, since all of these require so many parts, disadvantages arise and productivity is decreased and the manufacturing cost is increased.